I'd like an investigation of (if possible) Moon Gates and timer for Iria artifacts to poof after being discovered, and lastly, how the drops for iria exploration chests are decided.

For moon gates, I just want to know what their coding looks like? As humans have the current moon gate system, and pets still use the old moon gate system. Showing that moon gates weren't actually changed, just given a new coding, which sounds lagtastic honestly.

As for the second one, I'd love to find this so I know when NOT to pull something out of the ground so it doesn't auto poof before I can so much as finish hearing the music for digging it up.

For the last one, I'm going to go ahead and guess that it's the exact same way they do every other chest drop system in the game, that 'complicated' system for rolling a random number.

Moon Gates are quite possibly in the server binaries and out of our reach. I don't recall ever seeing a script for them. Aura's kicked moongates around, though, so you may be able to find some answers there.

Treasure box rewards are picked like most dungeon rewards and gachas. Standard while loop running the same case statement repeatedly to "roll through" the prize list and stop at a certain point.

As far as timers... oh geeze. If I'm reading it properly, there seem to be separate timers for groups of relic types, ranging from 90 to 360 seconds (in increments of 30 seconds or so). It's a big-ass list too, we're talking 10,000+ lines. Since the timers are server-sided I can't think of a way to predict them other than seeing when something else vanished and watching the clock to see when the type of relic you're after vanishes, and then just guessing from there.

I would like to see what sort of information you guys can dig up about combo cards. Which skills are eligible, how much damage can they add, and how do they interact with other multipliers (Flame Burst apparently only boosts the first attack/Magnum Shot doesn't stack w/bohemian, etc).

It would also be nice to see how the premium combo card slots are determined.

I want to find out how exactly does shooting rush damage work (if you just add up the 4 visually separate lines it doesn't always add up) and how its modifiers stack, but Rydian already mentioned damage dealt being server sided and it's a pain to do so looking at the numbers so guess there's not much to go with.

Combo cards have changed over time (such as the addition of gunning and puppetry some time in G19), anything we find wouldn't really be useful or current unless you want like the damage ranges per step (1-10%, 1-12%, 1-15%, 1-20%, 1-30% apparently).

Unfortunately actual skill mechanics including things like damage calculation are not scripted or data-based. They're compiled into the server binary and we can't look at any of that in any reasonable way.

...timer for Iria artifacts to poof after being discovered...
...
As for the second one, I'd love to find this so I know when NOT to pull something out of the ground so it doesn't auto poof before I can so much as finish hearing the music for digging it up...

It's timed, but not based on when they're discovered. All the ones of the same type on the same map that have been discovered dissapear at the same time. IIRC, chests in Courcle maps are cleaned up every 2 minutes and ones everywhere else are removed every 5 minutes, other things like the random statues in Maiz Prairie are separate.